Par-boiling or Par-baking Hasselbacks For Service?

So I want to put Hasselback potatoes on my menu, because they are >amazing<, but they take at least 40 minutes to cook. I want them to come out of the oven right before plating, and I want them to finish cooking at that time, not just get warmed up.

I have tried to par-boil them and par-bake them, but I haven't been able to do either of those with acceptable results.

I am vacationing in a camper with nothing more than a microwave and an overgrown camp stove with a big pretend Easy Bake Oven.
Have been experimenting with par cooking (even brownies) in the micro and finishing in the hot box.
Did some sweet potato fries last nite that were awesome.

Either way you will need to be carefull they don't steam to mush before you pull them.
My times have been unpredictable....depending on densities and inherent water content of the item.

I don't actually have a microwave, though that would probably be the easiest method. I suppose I can try steaming them, though I'm not sure about having them already sliced at that point? The deep fryer sounds tempting...

Nate, how long do you end up baking them after the nuke? And I'm curious about your cutting, because yours opened up a lot less than mine. How thick is the uncut part at the bottom? Mine also might be more open because I stuff them with slivers of garlic and green onion.

I slice raw, i have seen people put chop sticks, or wooden spoons down to slice into to prevent cutting all the way through, but i generally just go by eye... so my cuts are a little more uneven. I oil/butter after nuking rather than before so the starch can tend to stick the fans back together a bit. This helps me hold them longer/fresher.

I cook at 350 for for 15-30min and set to hold at 160, they hold well for around 2 hours.

After peeling and slicing, place them in a bath of salted water with ice for an hour before baking.
The water should be as salty as sea water.
Rinse the potatoes after soaking in several changes of water. Dry as best you can. Drizzle with olive oil/ butter then season.
The potatoes will bake faster (about 30 minutes at 450 convect) and have a crispier skin (I assume you baste). Try it....

Chefross, are you talking about Hasselbacks? They aren't normally peeled, just sliced almost all of the way through.

Brining them sounds interesting! I'll bet you could incorporate some flavors in that brine as well.

I'm also working in a small kitchen, with one oven usually set to 200C fan during service, so not so easy to hold them, and I don't really want leftovers, so I'm hoping to finish off the baking in the 15-20 minutes that it takes to cook the filet.

I used to split white potatoes, cut them crosshatch, roast on parchment lined sheet pan with olive oil & salt until just cooked through with no color, then cool them. For service they went into the fryer until golden then tossed with rosemary garlic butter.

Ive actually done this a couple times, what has worked for me is to par-bake in the oven and then I've moved them into my AltoShaam hold oven, essentially a slow cooker that can be a steamer or a smoker or just warmer to hold plates or warm sides. They last about 3 hours in the slow cooker before the skins get wrinkled, but the internals of the potato are consistently perfect.